The National Cancer Institute funded the planning and creation of the Childhood Brain Tumor Consortium (CBTC) in 1979 for the purposes of improving 1) the accuracy of prognostic information about children with brain tumors and 2) the classification of those tumors. The database contains 3291 children with brain tumors collected over a 50-year period from ten university-affiliated hospitals with information on 144 histologic features, 202 clinical variables and the World Health Organization (WHO) diagnosis for each child, as well as formal measures of within and between pathologist reliability for each histologic feature and WHO diagnosis. This is the largest database ever assembled about children with brain tumors. Histologic and diagnostic data were collected by CBTC neuropathologists trains to collect information objectively while being measured on their observational reliability. Another database with comparable high quality is unlikely to be assembled in the near future. Significantly preliminary and first round analyses have been completed since the first grant ended. The CBTC dataset will be analyzed by a Biostatistics/Epidemiology Group at The University of Southern California and the Childrens Hospital of Los Angeles. For goal 1, the analyses will determine from the large number of histologic features, clinical variables, tumor location, and WHO diagnosis for each child, which variables are best in mathematical modeling and thus predicting survival or morbidity. Tables and charts for physicians to use in order to provide parents with quantitative predictions of survival time and morbidity for their child with a brain tumor will be produced. For goal 2, relatively homogeneous groups of brain tumors will be sought without using the WHO diagnoses. The strategy will be to group analytically selected histologic features and clinical variables (perhaps by tumor location) into subsets which in turn can be used to analytically group children with brain tumors. We will then further subdivide these brain tumor sets by use of survival analytic methods using prognostic features not included in the grouping process. Criteria for identification of homogeneous groups thus will be based on the joint occurrence of selected histological features and clinical variables and on other features and variables which are important indicators of, or are at least associated with tumor aggressiveness. The resultant homogenous groups can be used in the future to select children for treatment efficacy (phase 2 and phase 3) clinical trials or for research on pathogenesis and etiology.